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Therapeutic hypothermia as a neuroprotective therapy after cardiopulmonary arrest in children

Cardiopulmonary arrest in children is uncommon however the numbers of children who survive are very low. Resulting brain injury in the survivors can be devastating for the child and family. Cooling the patient to a temperature of 32 °C to 34 °C, which is 3 °C to 4 °C below normal (therapeutic hypothermia), has previously been found to improve survival and reduce brain injury in newborn infants who were deprived of oxygen during birth, and also in adults following cardiopulmonary arrest. The causes of cardiopulmonary arrest are different in children than in adults, and asphyxia at birth is also different, so the effect of therapeutic hypothermia on the proportion of children who survive or who have brain injury is unclear.

We therefore conducted a Cochrane systematic review of the literature, searching medical databases (CENTRAL, MEDLINE, EMBASE) until December 2011 and contacting international experts for high quality published and unpublished evidence. Our searches failed to find any randomized controlled studies that met our inclusion criteria. However, we found four on-going trials which, when completed, may contribute to our review.

At present there is no evidence from randomized controlled trials to support or refute the use of therapeutic hypothermia within a few hours after return of spontaneous blood flow following cardiopulmonary arrest in children. International resuscitation guidelines currently recommend that doctors consider using the therapy in infants and children although more research is needed to be sure this is the correct recommendation with the lack of treatment options other than supportive care in an intensive care unit that are available.

Authors' conclusions:

Based on this review, we are unable to make any recommendations for clinical practice. Randomized controlled trials are needed and the results of on-going trials will be assessed when available.

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Background:

Cardiopulmonary arrest in paediatric patients often results in death or survival with severe brain injury. Therapeutic hypothermia, lowering of the core body temperature to 32 °C to 34 °C, may reduce injury to the brain in the period after the circulation has been restored. This therapy has been effective in neonates with hypoxic ischaemic encephalopathy and adults after witnessed ventricular fibrillation cardiopulmonary arrest. The effect of therapeutic hypothermia after cardiopulmonary arrest in paediatric patients is unknown.

Objectives:

To assess the clinical effectiveness of therapeutic hypothermia after paediatric cardiopulmonary arrest.

Search strategy:

We searched the Cochrane Anaesthesia Review Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 11); Ovid MEDLINE (1966 to December 2011); Ovid EMBASE (1980 to December 2011); Ovid CINAHL (1982 to December 2011); Ovid BIOSIS (1923 to December 2011); and Web of Science (1945 to December 2011). We searched the trials registry databases for ongoing trials. We also contacted international experts in therapeutic hypothermia and paediatriccritical care to locate further published and unpublished studies.

Selection criteria:

We planned to include randomized and quasi-randomized controlled trials comparing therapeutic hypothermia with normothermia or standard care in children, aged 24 hours to 18 years, after paediatric cardiopulmonary arrest.

Data collection and analysis:

Two authors independently assessed articles for inclusion.

Main results:

We found no studies that satisfied the inclusion criteria. We found four on-going randomized controlled trials which may be available for analysis in the future. We excluded 18 non-randomized studies. Of these 18 non-randomized studies, three compared therapeutic hypothermia with standard therapy and demonstrated no difference in mortality or the proportion of children with a good neurological outcome; a narrative report was presented.